Fuel burners and coal-water slurry burners are known in the prior art, wherein it is further known to provide oxygen enrichment, particularly oxygen enrichment of primary air. In U.S. Pat. No. 4,515,095 a process for combusting a coal-water slurry, wherein the primary air is enriched with oxygen, is identified in which it is reported that oxygen enrichment reduces the ignition time delay and brings the flame zone closer to the fuel burner nozzle.
U.S. Pat. No. 4,407,205 discloses coal combustion with swirling vanes for swirling combustion air.
U.S. Pat. No. 4,541,796 disclose a burner using oxygen enrichment, in which a plurality of oxygen jets surround the fuel jet nozzle.
U.S. Pat. No. 4,591,331 discloses a fuel burner for burning pulverized coal, having an inner fuel carrying passage and an outer oxygen-enriched combustion supporting gas passage.
U.S. Pat. No. 4,523,529 discloses a burner for the combustion of solid fuels, wherein oxygen jets surround the central fuel passage and the oxygen jets are in turn isolated by a blanketing shield of moderator gas in an annular passage.
U.S. Pat. No. 4,519,322 discloses a burner for coal-water slurries with circumferentially overlapping vanes mounted concentric to the fuel supply means.
U.S. Pat. No. 3,124,086 discloses a burner having tangential oxidant supply lines to the central fuel delivery line.
U.S. Pat. No. 4,193,773 discloses a burner for combusting pulverized coal wherein oxygen is supplied from a manifold having both perpendicular and tangential apertures opening into the coal supply line.
Although the prior art describes oxygen enrichment of primary air in a burner to the extent of 22 to 25 percent oxygen in the total air supplied to the burner and the beneficial effect this has on the combustion of coal water slurries, this is generally accomplished by homogeneous mixing for upstream of the burner. The present invention enhances operation over the prior art by providing higher oxygen concentrations in the immediate vicinity of the combustion.
All of the prior art describes burner designs which fail: (a) to encompass a blending and intermixing of the oxygen readily with fuel to stabilize the fuel flame, and (b) to avoid direct contact of the oxygen delivery source with the fuel delivery source, which would degrade the burner by fuel or carbon deposits which exceed, in conjunction with the oxygen, material temperature design limits. The present invention, as set forth below, overcomes these drawbacks.